L10 Icing

Flashcards about Icing

Is icing hazardous to aircraft?

Any form of icing is a hazard to an aircraft.

How does ice affect an aircraft's drag and lift?

Markedly increase drag and reduce lift.

What can happen to an aircraft's flight characteristics when affected by ice?

It becomes uncontrollable.

What can engine icing cause?

A marked reduction in power, or even a total failure.

What can ice do to the pitot and static pressure sources?

Block the external pitot and static pressure sources.

What can ice do to the flying controls?

Freeze the flying controls solid.

What type of flight conditions is a potential icing situation?

Flight in cloud at temperatures below 0°C.

What is a common characteristic of light aircraft regarding de-icing equipment?

They are not fitted with de-icing equipment.

What does the POH/FM state about flight into known icing conditions for light aircraft?

The machine is not cleared for flight into known icing conditions.

What happens to water droplets in a cloud?

Water droplets can remain liquid at temperatures well below freezing.

How low can the temperature be for water droplets to remain liquid in a cloud?

As low as -40°C or even colder.

Where is an aircraft in potential icing conditions relative to the freezing level?

Above the freezing level.

What is the semi-opaque coating of ice called?

Rime ice.

Where does rime ice usually form?

On the leading edges of the wings and tail and also on aerials, struts, etc.

What is the sheet of clearer ice called?

Clear ice.

What OAT range is considered the worst for icing?

Between 0°C and -12°C.

What do clouds mostly consist of at temperatures below -40°C?

Ice crystals.

Where can severe icing be encountered at any temperature below 0°C?

Within a cumulonimbus cloud.

Which cloud type tends to hold larger water droplets?

Cumuliform clouds.

Which cloud type can sometimes give unexpectedly severe icing?

Stratocumulus.

What should you do if caught out in icing conditions?

Select the pitot heat immediately.

What type of frost can form on an aircraft before it has even left the ground?

Hoar frost.

When does hoar frost form?

When the water vapour in the atmosphere changes directly from a gas to a solid.

How will frost affect the aerodynamics of the aircraft?

It will have a dramatic effect on the aerodynamics of the aircraft.

What are the effects of even a thin layer of frost on an aircraft?

It reduces lift, increases drag, raises the stalling speed and can make the aircraft difficult to control or even unflyable.

What performance reductions can frost result in?

Longer take-off and landing distances, reduced climb rates, cruising speeds and range.

What must be done with frost before flight?

All the frost must be removed from all the aircraft surfaces.

What must a pilot do with snow on the aircraft before takeoff?

The pilot must remove all the snow from all the aircraft before take-off.

Where can hoar frost form on an aircraft in flight?

In an area of warmer and possibly more moist air.

What usually happens to frost forming after climbing through an inversion?

Thaws quickly.

What uncommon form of icing can occur outside cloud?

Rain ice.

What is the classic environment for rain ice?

The area just ahead of a warm front in winter.

What happens when rain meets an object whose surface temperature is below freezing?

The rain drops may freeze on contact - forming lumps of clear ice which are difficult to remove.

What is the only real solution to rain ice?

Avoidance.

What is the ICAO definition of the 'Clean Aircraft Concept'?

Take-off shall not be attempted when ice, snow, slush or frost is present or adhering to the wings, propellers, control surface, engine inlets or other critical surfaces.

How does ice, snow, or frost affect aircraft performance?

Reduced aerodynamic lift and increased drag.

What is the process which removes ice, snow, slush or frost from aeroplane surfaces?

De-icing.

What is a precautionary measure that protects clean aeroplane surfaces against ice formation?

Anti-icing.

What type of fluid is commonly used to de-ice GA aeroplanes?

Fluid based on ethylene glycol.

Who is responsible for ensuring that the critical surfaces of the aircraft are free of ice, snow, slush or frost just prior to take-off?

The pilot-in-command.

What is the most common form of ice-related problem which afflicts a piston engine?

Carburettor icing.

What does the combined effect of the fall in pressure within the venturi and the evaporation of the fuel lead to?

A very large decrease in the temperature.

How much of a temperature drop is usually expected in the venturi?

A temperature drop of around 25 to 30°C.

What happens to water vapour in the venturi?

Water vapour almost inevitably forms into ice crystals which stick inside the venturi.

What is the dominant factor in carburettor icing?

The moisture content of the air.

How does air temperature affect moisture content?

Warm air can hold more moisture than cold air.

What are the obvious danger signs of carburettor icing conditions?

Visible moisture such as clouds, fog and precipitation.

When is carburettor icing a particular danger?

At low power settings.

At what OATs should the temperature reduction in the carburettor not take the air temperature below freezing?

At OATS above +30°C.

At what temperatures is moisture likely to become dry ice crystals?

At temperatures below -10°C.

Where can further information and advice on carburettor icing be found?

The POH/FM, AICS and in other safety information published by safety bodies and aviation authorities.

Where can ice form on the propeller blades?

Ice may form on the propeller blades.

What does the resulting mechanical imbalance cause?

The resulting mechanical imbalance also results in considerable vibration.

What type of flying should pilots avoid to prevent the chances of encountering engine icing?

Flight in conditions that could result in it.

Are the definitions used for pilots reporting icing the same as the criteria used to forecast icing?

They are not the same as the criteria used to forecast icing.

What is the definition of "trace" icing?

Icing is just perceptible, and not hazardous even if de-icing or anti-icing equipment is not used unless encountered for more than one hour.

What action is recommended by the definition of severe icing?

Immediate diversion necessary.

What is the definition of "light" icing?

Rate of accumulation might be a problem if conditions persist for more than one hour.

What is the definition of "moderate" icing?

Even short times in these conditions are potentially hazardous.

If there is ice, snow, slush, or frost on the plane, who is responsible for removing it?

The pilot-in-command.

What is the chief factor in the likelihood of carburetor icing?

The moisture content of the surrounding air.

Which of the four classifications of icing is the most severe?

Use of de-icing or anti-icing equipment fails to reduce or control icing accumulation.

What are the main methods used to de-ice light aircraft?

Mechanical methods and/or chemical methods

What effect does ice have on lift, drag, and stall speed?

Ice reduces lift, increases drag, raises the stalling speed and can make the aircraft difficult to control or even unflyable.

What causes rain ice?

The freezing of rain on contact with the aircraft surface.

What is the relationship between airframe and engine icing?

Airframe icing can also cause engine icing.

What is the difference in consistency in rime and clear ice?

Rime ice is brittle and semi-opaque, while clear ice is denser and more tenacious.

Besides temperature, what factors can influence icing severity?

Cloud type and water droplet size

What are visible indicators of potential carburetor icing?

Clouds, fog, precipitation, moist airflow from over the sea

What temperature condition is unique within a cumulonimbus cloud?

Severe icing can be encountered at any temperature below 0°C within a cumulonimbus cloud.

According to the "Clean Aircraft Concept" who is in charge on the ground?

The pilot

What is the danger of ice accumulation in the pitot and static tubes?

The pressure instruments to become unreliable

Before you take off after a snow shower, what steps must a pilot take under the "Clean Aircraft Concept"?

Remove all the snow from all the aircraft surfaces

What are the different measures of ice accumulation?

Severe, moderate, light and trace

Under ICAO how can a plane be protected from dangerous ice?

De-icing and anti-icing

Where is freezing rain occurring according to the notes?

At several Scottish airports (including Dundee and Inverness), freezing drizzle (FZDZ) and freezing rain (FZRA) are occurring

What does the graph focus on to show when Carburettor Icing is most likely?

The graph concentrates on the temperature and humidity.

Besides the wing, where else can ice build and cause problems?

The external pitot and static pressure sources

What can drastically effect the performance of a plane?

Reduced aerodynamic lift and increased drag

What is usually used to de-ice GA airplanes and other machines?

Ethylene glycol

What is likely to happen if frost forms after climbing into warmer air?

It thaws quickly

On a Piston Engine, where can ice form?

The propeller blades

Are the guidelines for pilots reporting ice the same as the one used to forecast?

They are not the same

Based on the report listed, what is the Q1014

Dundee EGPN 211050Z 29004KT 9000 FZDZ SCT035 BKN045 M00/M01 Q1014

Regardless of the ground crew, whose responsibility is it to make sure the plane is safe?

The pilot

Under which conditions does Ram Ice Occur?

Freezing of rain on an object

What is the difference of anti-icing versus de-icing?

De-icing removes ice, snow, slush or frost. Anti-icing protects the plane against them happening

What is the classic environment for rain ice?

The area just ahead of a warm front in winter.

When de-icing, what should be focused on?

All aircraft surfaces, even if you think, like snow, the excess will burn off

What should be noted when snow settles over wing fuel tanks?

They tend to be cool

Under what conditions will a Rime Ice occur?

Rime ice typically occurs when an aircraft meets a small supercooled water droplet

Where can icing definitions be found?

The aircraft's flight manual or de-icing equipment handbook:

What qualification does a PPL pilot need to fly in clouds?

The PPL Pilot is not qualified to fly in clouds

When it comes to icing, what is the best solution?

Avoiding them

When reporting icing, what should you mention?

When reporting icing remember to include the 'when and where'.

How should ice on an aircraft used by GA be removed?

It should be removed mechanically or chemically

What state does water need to be to produce hoar frost?

A gas to a solid

Where does carburettor icing stick to within a machine?

In the venturi

What are the following definitions used for?

They are those used for pilots reporting the intensity of icing

What part of a standard piston engine gets ice?

The engine air intake